1. Field of the Invention
This invention relates to a spring loaded friction clutch, and, more particularly, this invention relates to means for adjusting for wear in the friction surfaces of the clutch in a manual or automatic wear adjustment system.
2. State of the Art
In manual and automatic wear adjustment, compensation for wear in the friction surface is accomplished by movement of an adjusting ring, relative to the clutch cover closer to the clutch disk. Typically, actuating levers which push against the pressure plate are pivoted on the adjusting ring so that axial movement of the ring towards the pressure plate will adjust for wear. The adjusting ring is threaded at its periphery to engage threads in a flange of the cover. As the adjusting ring is unthreaded, it moves axially towards the pressure plate. Approximately 1/2" of axial movement of the adjusting ring is required for the full life of the clutch. This 1/2" of movement is equal to approximately 720.degree. of rotation of the adjusting ring. With this arrangement, the rate of adjustment for wear can be too slow causing more slippage and, therefore, more wear. The threaded connection provides good concentricity of the parts, but the threads fret and corrode so that they often become frozen and cannot be rotated according to their original design. Grease is usually required to reduce the fretting, corrosion and wear of the threads themselves.